Color-forming photographic process utilizing a bleach-fix followed by a bleach



June 15, 1965 COLOR-FORMING PHOTOGRAPHIC PROCESS UTILIZING A DENSITYDENSITY c. c. BARD ETAL $189,452

BLEACH-FIX FOLLOWED BY A BLEACH Filed Dec. 5, 1961 12,-\ YELLOW DYEDENSITY DYE DENSITY l l l l I I l l l l 1 4! DYE DENSITY MAGENTA DYEDENSFE'Y 1 I I i l l l 1 l l I l I I i I Chaz'leton G Bard GeorgeRVarZan INVEN TORS 311%Z4-[M WW m Arrows United States Patent Ofi icePatented June 15, 196-5 CSLOREGRMENG PHQTGGEEAPHEC PROCESS A BLEACHCharleton C. Bard and George P. Varlan, Rochester, N.l., assignors toEastman Kodak Company, Rochester, N.Y., a corporation of New EerseyFiled Dec. 5, 1961, fier. No. 157,096 4 (Ilaims. (Cl. 96-55) The presentinvention relates to photography and particularly to the processing ofcolor photographic materials. Still more particularly, the inventionrelates to a shortened method for the processing ofcoupler-incorporating, colorforming photographic films and prints.

In the usual method for processing of exposed multilayercoupler-incorporating, color-forming photographic materials, the colordeveloper bath is usually followed by consecutive baths comprising afix, a bleach, and a fix again with an intervening wash step betweeneach of the baths indicated. As is well known, the fix bath is employedto remove the undeveloped silver halide from the developed emulsionlayers while the bleach bath is employed to oxidize the metallic silverformed by development to silver halide. The second fix is normallyemployed to remove the silver halide formed by the previous bleachingstep so that the emulsion layers are cleared of residual silver andsilver halide. This leaves essentially a colored image of cyan, magenta,and yellow dye densities as formed at the time of development bycoupling of the incorporated couplers with oxidation products of aprimary aromatic amino developing agent contained in the color developerbath.

It has been of interest for some time to shorten the time required forprocessing of color-forming photographic materials. 'Ihe presentinvention has quite unexpectedly found a shortened method for theprocessing of certain color-forming photographic materials withoutsacrifice in image quality and which is adapted for use in theprocessing of photographic materials of a high silver content. By highsilver content in the present specification, we mean materials having asilver content of 200 mg. per square foot or higher. The image qualityobtained according to the present invention is illustrated in theaccompanying drawing in which:

FIG. 1 shows the colored image densities obtained in a standardphotographic process FIG. 2 shows the colored image densities obtainedusing the present shortened process.

Accordingly, it is an object of the present invention to provide a novelshortened process for the processing of color-forming photographicmaterials. A second object is to provide processing baths for use insaid shortened process. Other objects will become apparent from areading of the specification and appended claims.

These objects are accomplished by treating an exposed color-formingphotographic material of the invention, after color development andwashing, with a combined bleaching and fixing solution followed by aseparate bleaching solution. According to the invention, an interveningwash between the treating baths of the invention is not required. Afterthe bleaching bath of the present process, the photographic material canbe washed and then treated with a conventional bufier bath, if desired,as normally employed in the art.

Photographic materials of the type processed according to the presentinvention comprise materials having color-forming couplers contained inrespective layers of a multilayer photographic element. Materials ofthis type have been described in a number of US. and foreign patents,for example, in US. Patents 2,322,027, Tune 15, 1943; 2,407,210,September 3, 1946; 2,474,293, June 28, 1949; 2,640,776, June 2, 1953;and 2,956,876, October 18, 1960. Color films of the invention includethe so-called negative-positive type materials as well as reversalmaterials. The photographic multilayer color materials of the inventioncomprise elements having usually three selectively sensitive emulsionlayers coated on one side of a photographic support. Sensitive layers ofthe elements of the present invention contain color-forming couplers toform the complementary dye to wmch a particular layer is sensitive. Insensitive materials of this type, the uppermost layer is generallyblue-sensitive and normally in corporates a yellow-forming coupler. Thenext layer generally comprises a filter layer which is yellow in colorand blue absorbing and being placed under the top layer absorbs most ofthe blue light thus preventing unwanted blue exposure below the filterlayer. The next layer is generally green-sensitive and usuallyincorporates a magenta-dye forming coupler. The emulsion layer adjacentto the support is generally red-sensitive and according to the presentinvention normally contains a cyan-dye forming coupler. Sometimesmultilayer photographic elements as used in the present inventioncontain additional silver halide emulsion layers or other interlayersfor specialized purposes. In photographic print materials, frequentlythe yellow filter layer is omitted and the arrangement of silver halideemulsion layers may be changed for the purpose of obtaining moreaccurate recording of the color negative.

In accordance with the present invention, the combined bleaching andfixing solution can be prepared by combining a number of silverbleaching agents and silver halide fixing agents. For example, wherefreshly prepared combined solutions can be employed, a suitablebleaching agent can comprise an alkali metal dichromate (e.g., sodiumdichromate, and potassium dichromate), an alkali metal ferricyanide(e.g., potassium ferricyanide, and sodium terricyanide),ferricyanide-bromide, permanganate (e.g., potassium permanganate),quinone, and the like. Such bleaching agents can be combined in freshlyprepared solutions with such fixing agents as alkali metal thiocyanates(e.g., sodium thiocyanate and potassium thiocyanate), ammoniumthiocyanate, alkali metal thiosulfate (e.g., sodium thiosulfate andpotassium thiosulfate), ammonium thiosulfate, thioureas, and alkalimetal selenocyanates (e.g., sodium selenocy anate and potassiumselenocyanate). Combined baths of this type, however, are stable over avery short period of time; and, consequently, optimum results can beobtained using fresh solutions only. Some improvement in stability insuch baths can be obtained by the addition to the bath of a thicken-ingagent which results in the formation of a viscous solution. Such viscoussolutions can be applied as a surface layer on the photographic materialto be processed. Suitable thickening agents for this purpose include awide variety of materials, such as carboxymethylcellulose,ethylcelluiose, gelatin, poly-vinyl alcohol, collod-ion, polyvinylacetals, cellulose esters, and the like.

More stable combined bleaching and fixing solutions comprise, forexample, a ferric chloride solution containing a sequestering agent suchas ethylene diamine tetra-v acetic acid tetnasoclium salt, and a fixingagent such as sodium thiosulfate. Other combined solutions of the j .Theseparate bleaching solution for use in the present invention can beprepared by dissolving an appropriate amount of a silver bleaching agentof the type mentioned baths have been described, for example, in US.Patents 2,745: ,000, May 29, 1 956; 2,113,329, April 5, 1938; and2,252,718, August 19, 1941.

Photographic silver halide emulsions useful in the process of thepresent invention can be prepared according to known methods such asthose described in Hewit- -s on and McClintock, US. Patent 2,618,556,November '18, 1952. Emulsions prepared by other methods can also 1 ganicand have boiling points above about 175 C. These cellulose nitrate,etc., water-insoluble, but Water-permeable cellulose ethers,Water-insoluble but water-penneable natural and'synthetic resins,high-boiling, substantially Water-insoluble crystalloidal materials,such as N-n-aniylphthalimide, tetrahydrofurfuryl benzoate, triphenylphosphate, n-butyl phthalate, and the like (see also U.S.

2,801,717). r Our invention isespecially. useful with emulsions in whichthe color-former is dispersed in one or more of the aforesaidsubstantially water-insoluble, high-boiling, crys talloidal materials.These crystalloidal materials are orcrystalloidal materials have a highsolvent action for the i be used to equal advantage in the invention.These emulsions can be sensitized, for example, with chemicalsensitizers as described in US. Patents 2,540,085; 2,597,856; and2,597,915; with azaindene compounds as disclosed in US. Patent2,716,062; with condensation products of alkylene oxides as described inUS. Patent 2,400,532,- and with the additives as mentioned in US. Patent2,937,- 3089. In short, the photographic emulsions of the invention cancontain addenda or not, as Well known in the art, to improve thecharacter of such emulsions.

: Photographic elements of the present invention can be prepared byemploying any of the emulsions previously described. Emulsions of thepresent type can be coated as separate layers on typical supports asused in preparzing such photographic elements, such as cellulose acetatefilm, resin film, paper etc. elements of the invention which containseparate layers and are therefore referred to as multilayer materialshave been described in such US. Patents as 1,055,155, 2 March 4, 1913;2,304,940, December 15, 1942; and 2,322,- 027, June 15, 1943. Thepresent invention is also applicable to color photo- 'g-naphic emulsionmaterials wherein the emulsions are 1 mixed instead of disposed inseparate layers. Moreover, particular emulsions can be employed in theinvention which comprise single emulsions containing color tormers formaking component color pictures. The emulsions of the present invention,in addition to containing color- 1 formers (couplers) as previouslyindicated, can also con- ;tain sensitizing dyes in addition to the usualaddenda' j employed in emulsions of the present type.

permeable materials set forth in U.S.'Patents 2,304,940

and 2,322,027, such as Water-insoluble but water color-formers and forthe dyes formed therefrom andare permeable to photographic processingsolutions. These crystalloidal materials have been referred to as oilformers because they have the property of producing an oily or liquidsolution when mixed with the coupler, even though the cou ler is asolid. The crystalloidalmaterials. are generally liquid'at ordinarytemperatures or low melting solids (below 100 C.), The most usefulcompounds contain one or more polar groups such as'halogen, hydroxyl,carboxylic acid, amide, ketone, etc.

The following couplers are suitable for use in our inven-- tion. It isto be understood that this list is not exhaustive, but merely to typifycompounds which maybe used."

Courrans PRODUCING CYAN IMAGES 5- (p-amylphenoxybenzenesulfonamino) -l-naphtho1 5- ('N-benzyl-N-naphthalenesulfonamino) -1-naphthol5-(n-benzyLN-n-valerylamino)-1-naphthol S-caproylarnino-l-naphthol V2-chloro-5 (N -n-valeryl-N-p -is opropylbenzylamino) ,-1-

naphthol 2,4-dichloro-5- (p-nitrobenzoyl-fl-o-hydroxyethylamino)1naphthol 2,4-dichloro-S-palmithylamino-l-naphthol 2,2'-dihydroXy-5 ,5-dibromostilbene 5-diphenylethersulfonamido-l-naphthol Typicalphotographic Any of the acylaminophenolcouplers disclosed in UnitedStates Patents 2,423,730, dated July 8, 1947, can also a be used ascouplers for the cyan image.

The emulsions of the present photographic elements a permeable celluloseesters, e.g., Water-insoluble, but waterpermeable cellulose acetate,cellulose acetate-phthalate,

Courrens PRoDUcrNo MAGENTA IMAGES l-p-sec.amylphenyl-3-n-amyl-5-pyrazolone 2-cyanoacetyl-5- (p-sec.,amylbenzoylamino)rcournarone 2-cyanoacetylcoumarone-i(N-n-amyl-p-tert.amylsulfanilide.) 2-cyanoacetylcoumarone-5-sulfon-N-n butylanilide2-cyanoacetyl-5-benzoylaminocoumarone 7 Z-cyanoacetylcoumarone5rsulfondimethylamide Z-cyanoacetylcournarone 5-sulfon-N-methylanilideZ-cyanoacetylcoumaron e-5- (N- y-phenylpropyl) -ptert, amylsulfonanilideV 1-p-laurylpheny1-3 -methyl- 5-pyrazolone l-{i naphthyl-3-arnyl-5pyrazolone l-p-nitrophenyl-Z-n-amyl-5-pyrazolone' 7 lfi-phenylenebis-3%l-phehyl-S-pyrazolone) r I V 1-phen'yl-3 acetylamino-5-pyrazoloneCOUPLERS PRODUCING YELLOW IMAGES N-amyl-p-b enzoylacetaminobenzenesulfonate N- (4-anisoylacetaminobenzenesulfonyl) -N-benzyl-mtoluidine N- (4-b enzoylacetaminobenzenesulfonyl) -N-benzyl-mtoluidine N- (4-benzoylacetaminob enzenesulfonyl)-N-n-amyl-ptoluidine N- (4-benzoylacetaminob enzene sulfonyl)-N-benzylaniline wp-B enzoylb enzoyl) acetanilide w-Benzoylacet-Z,S-dichloroanilide w-Benzoyl-p-sec. amylacetam'lide N ,N-dio-benzoylacetyl) -p-phenylenediamine N,N-di- (acetoacetamino) diphenyl4,4-di acetoacetamino) -3 ,3 '-dimethyldipheny1 p,p'-Di-(acetoacetamino)diphenylmethane Ethyl-p benzoylacetaminobenzenesulfon ate N onyl-p-benzoylacetaminob enzenesulfonate N-phenyl-N- (p-acetoa cetaminophenyl)-urea In the development of exposed photographic silver halide emulsionlayers using the couplers of our invention, any color-forming developercontaining a primary amino group may be used. These include developershaving two primary amino groups as Well as those having one of the aminogroups substituted or having substituents in the ring, such as the alkylphenylene diarnines. These compounds are usually used in the salt form,such as the hydrochloride or the sulfate which are more stable than theamines themselves. The suitable compounds are diethyl-p-phenylenediaminehydrochloride, monomethyl-pphenylenediamine hydrochloride,dimethyl-p-phenylenediamine hydrochloride, andZ-amino-S-diethylaminotoluene hydrochloride. The p-amino phenols andtheir substitution products may also be used where the amino group isunsubstituted. All of these developers have an unsubstituted amino groupwhich enables the oxidation products of the developer to couple with thecolor-forming compounds to form a dye image.

The color-formers (couplers) can be incorporated in the emulsions in thecustomary manner, e.g., by adding a dispersion of the coupler in awater-insoluble but waterpermeable material to the emulsion as indicatedpreviously, or by adding a dispersion of the alkali metal of the couplerin water. Couplers can also be added to the emulsion in crystalloidalmaterials such as oil-boiling organic crystalloidal materials to producean oil-like misture which can then be dispersed in water or a binder ofcolloidal character as well known in the art. (See for example U.S.Patent 2,640,776.) Dispersion of the coupler in a binder can be efiectedwith the aid of a homogenizer, a colloid mill, or the like; anddispersions can be stabilized by the addition of emulsifying agents alsowell known in the art.

sensitizing dyes of the type previously indicated normally are added tothe emulsion before the coupler or coupier dispersion is added. (See forexample US. Patent 2,640,776 and 2,407,210.) Typical sensitizing dyesfor use in emulsions of the invent-ion have been described in a numberof U18. and foreign patents, for example, US. Patents 2,478,366, August9, 1949; 2,213,238, September 3, 1940; 2,231,658, February 11, 1941; and2,515,- 913, July 18, 1950.

To further describe the invention, reference will now be made to thefollowing examples.

EXAMPLE I A multilayer photographic element of the type described inJelley and Vittum U.S. Patent 2,322,027, issued June 15, 1943, was usedas the multilayer sensitive element. Separate elements of the typedescribed were given a like exposure to a colored image in theusualmanner and processed according to the following procedures in which oneof said elements was processed in a conventional manner (Process A) andthe second element was processed according to the present invention(Process B).

Process A (70 F.)

Time

Color develop a- 7 min. 30 sec. Wash -15 sec. Fix 4 min. Wash -4 4 min.Bleach 8 min. \Vash 4 min. Fix 4 min. Wash 7 min. Butter 1 min.

Wash 2 sec.

Total time 39 min. 47 sec.

Process B (70 F.)

Time

Color develop 7 min. 30 cc. Wash 15 sec. Acid stop 2 min. Bleach-fix 4min.

Bleach 4 min.

Wash 7 min.

Buffer 1 .min.

Wash 2 sec.

Total Time 25 min. 47 sec.

The processing solutions had the following to'rmulations:

COLOR DEVELOPER Water ml 950.0 Benzyl alcohol ml 3.8 Sodium sulfite 02.] Sodium hydroxide g 0.45 '4 amino N ethyl N(fi-methanesul-fonamidoethyl) meta toluidine sesquisulfate monohydrate g5.0 Sodium bromide g 0.86 Sodium carbonate (anhydrous) g .2.7 Water tomake 1.0 liter. pH 10.75 at 70 F.

FIX BATH Water ml 600.0 Sodium thiosulfate g 240.0 Sodium sulfite g 15.0Glacial acetic acid g 13.4 Boric acid g 7.5 Potassium alum g 15 .0 Waterto make 1.0 lite-r. pH 4.2 at 70 F.

BLEACH BATH Water ml 800.0 Potassium ferricyanide Q g 50.0 Potassiumbromide g 20.0 Water to make 1.0 liter. pH 6.5 at 70 F.

BUFFER BATH Water -m1 800.0 Disodium hydrogen phosphate g 8.2 Glacialacetic acid ml; 4.5 Water to make 1.0 liter. pH 5.0 at 70 F. V,

. ACID STOPVBATH Water ml 600.0 Sodium sulfite g 15.0 Glacial aceticacid ml 15.0

\Vater to make 1.0 liter. Adjustment to final pH of 4.2 using aceticacid or sodium hydroxide as required.

Sodium sulfite 15.0 pH 7.0 8.t70F.

In either of the processes of the example; color develop-l merit formedsilver, cyan magenta, and'yellow dye densities in the. sensitive layersof the element; and after development in each process, 'ithe emulsionlayers were cleared of silver and silver halides, leaving the respectivedye densities in situ. V 7

Process A. a conventional process, requirerl'39 minutes,

.47 seconds and employed ten steps including development,

pvhereas processing according to the present invention (Process B)required25 minutes, 47 seconds and employed eight steps. The process ofthe present invention, in effect, reverses the normal processing orderby employ ing a bleach bath'subsequent to a fixing bath to clear thephotographic material of silver and silver halide from the emulsionlayers. a e

The sensitometrie results of the example are shown in the accompanyingdrawing in which FIG. 1 shows the sensitornetric curves obtained fromthe material processed according to Process A and 'FIG. 2 shows thesensitometnic curves obtained in a comparable element processedaccording to Process B.

More particularly, in FIG. 1, sensitometric curve shows the integralcyan dye density of the prowssed element as measured in a Well knownmanner on an Eastman Electronic densitometer using a tungsten lightsource and red-light transmitting filter. Sen-sitometric curves 11 and112 show the integral magenta and yellow dye densities,-

respectively, as measured in like manner using a greenlight transmitting"filter .for the magenta dye density determination and a blue-lighttransmitting filter for the yellow dye density determination.

In 1 16. 2, sensitometric curves 13, 14, and show, respectively, thecyan, magenta and yellow integral dye densities obtained in like mannerin the element processed according to Process B. The densitymeasurements were made employing, respectively, red-, greenandblue-light (transmitting sources as in the 'FIG. 1 determination. Theretention of silver in the elements processed in l the present examplewas in each' case 1 mg. or less p r square foot for theelementsprocessed according to either of Processes A or B as determined in awell known manner, for example, by X-ray'fiuorescence analysis. The ele-.rnents .usedin the present example contained in excess of 200 mg. ofsilver per square foot prior to processing.

EXAMPLE II Separate multilayer photographic elements of the type used inExample I 'wereexposed to a multicolored image in a well known 'mannerafter which one strip was processed according to a conventional process(Process C) and the second strip was processed according to the processof the present invention (Process D).

Process C 7 :Min.

; Color develop 12 Benzyl alcohol ml 12.6 Sodium heXametaphospha-te g2.0 Sodium sulfite g 2.1 0 Sodium carbonate g 26.8 Potassium bromide g0.48 Sodiumchloride g 0.70

r G. Boric acid 5.0 Potassium alum 24.0 Sodium thiosu iate u 223.0Sodium. bisulfite 12.0 Sodium acetate (desiccated) 14.0 Sodium citrate(desiccated) 1.7 Water to 1.0 liter. v pH 4.40 at F.

BLEACH BATH 1 G. Sodium nitrate V 45.0 Potassiumrferricyanide r225Potassium bromide 8.2 Boric acid V 7.5 Borax 0.97 7 Water to 1.0 liter.

pH 7.30 at 75 F.

HARDENER-FIX BATH G. Glacial acetic acid 15.0

Zinc sulfate 7 l i V 7.5 Sodium citrate V 2.5 Zircotan 0.46 Sodiumbisulfite 17.9 Boric'acid r 17.2 Potassium. alum 35.5 "Sodiumthiosulfate 1.67.7 Water to 1.0 liter. 7 V a a pH 4.40 at 75 F. V

' FORMALIN-HARDENER BATH. Calgon (sodium hexametaphosphate) g 0.75Sodium carbonate g 8.8 'Formaldchyde (37% solution) ml 25.5

Water to 1.0 liter. 0

f ProcessD Color develop l Acid-hardener bath' l 2 Bleach-fix p '2Bleach '4 Wash 8 Buffet} 3 Total time 29 The processing solutions notpreviously disclosed had the following formulations:

.coLo R DEVELOPER Hydroxylamine sulfate g 2.1 4 amino N ethylN-(,B-rnethanesulfonamidoethyl) -rn et a-toluidine sesquisulfatemonohydrate g 4.2 Water to 1.0 liter. pH 9.96 at 75 STOP BATH Glacialacetic acid ml 17.0 Sodium sulfite g 20.0 Water to 1.0 liter. pH 4.64 at75 F.

mnscu FIXING BATH The processing time for the standard process (ProcessC) of the example was 43 minutes as compared to a 29- minute processtime for Process D. Substantially the same sensitometric results andsilver retention were obtained in either case. Each element contained anexcess of 200 mg. of silver per square foot prior to processing.

EXAMPLE HI Separate strips of a photographic material of the typedescribed in Jelley et al. US. Patent 2,322,027 coated on a papersupport were exposed to a multicolored positive transparency in theusual manner and processed separately according to the followingprocedures, in which Process E is a standard reversal process andProcess F is a reversal process of the present invention.

Process E Presoak 2 min. Drain 2 min. First developer 6 min. First stop3 min. Wash 7 min. 15 sec. Reversal exposure:

Color develop 7 min. 15 sec. Second stop 3 min. Wash 7 min. 15 sec.Bleach 7 min. 15 sec. Wash 7 min. 15 sec. Hardener-fix 7 min. 15 sec.Wash 14 min. 30 sec. Stabilizer 1 min.

Total processing time 75 min.

Process F Presoak 2 min. Drain V 2 min. First developer 6 min. Firststop 3 min. Wash 7 min. 15 sec. Reversal exposure:

Color develop 7 min. 15 sec. Second stop 3 min. Bleach-fix 4 min.

Bleach 4 min. Wash 14 min. 30 sec.

Stabilizer 1 min.

Total processing time 54 min.

Processing solutions used in the present example which have not beenpreviously disclosed herein had the following formulations:

FIRST DEVELOPER N-methyl-p-aminophenol sulfate g 0.9 Sodium sulfite g8.0 Hydroquinone g 2.35 Potassium bromide g 0.55 Sodium metaborate (8HO) g 25.5

6-nitrobenzimidazole nitrate (0.5% solution) ml 12. Water to 1.0 liter.pH 10.03 at 75 F.

FIRST lSTO'P BATH Sodium acetate 8.0 lacial acetic acid 19.0

Water to 1.0 liter. (Adjust to pH 3.7 at 75 F. using sodium hydroxide.)

SECOND STOP BATH Potassium iodide 2 0.2 Sodium bisulfite g 15.0 Glacialacetic acid m1 20.0 Potassium alum g 30.0

(Adjust to pH 3.0 using sodium hydroxide or sulfuric acid as required.)

BLEACH BATH.

The process time in the present example was shortened from 75 minutes to54 minutes and resulted in reduced stain density according to thefollowing data.

Stain Density Red Green Blue- Process E 22 22 26 Process F 18 17 18Change in stain density 4 5 9 The stain densities were measured in awell known manner by reflection densitometry in which the integral dyedensities in the cyan, magenta, and yellow were determined using red-,greenand blue-transmitting filters, respectively.

In the present process, good image densities are obtained presumablysince the invention permits the use of a final bleach which oxidizesleuco dye present to full color intensity. The photographic materials ofthe previous examples contained in excess of 200 mg. of silver persquare foot. The silver retained after processing was equal to or lessthan the silver retention in conventionally processed elements whichinvolved more time and a greater number of steps. Photographic materialshaving from 200 to about 600 mg. of silver per square foot can beprocessed to an optimum photographic result by way of the presentinvention.

The invention has been described in detail with parjticular referencevto preferred embodiments thereof but it will be understood thatvariations and modifications jean be eflected Within the spirit andscope of the inven-' ;tion as described hereinabove and as defined inthe ap- .spen-ded claims. i

Q We claim: 1.,In the color processing of an'exposed photographic silverhalideemulsion' layer containing a color coupler fthat has been colordeveloped to form a dye image, the improvement which comprises treatingthe said color Ideveloped emulsion layer with an aqueous solutionconftaining ferric chloride and a thiosulfate silver halide :solvent andthereby solubilizing'and'rernoving silver and .silver halide from saidemulsion layer, and thereafter further treating the resulting emulsionlayer with an aqueous solution containing a ferricyanide silveroxidizi12 agent and thereby oxidizing leuco dye in said emulsion layerto full color" intensity; I g

2. In the color processing of an exposed photographic silver halideemulsion layer containing a color coupler that has been color developedto form" a dye irnage, the improvemnt which comprises treating the saidcolor developed emulsion layer with an aqueous solution containingferric chloride and an alkali metal thiosulfate and thereby solubilizingand removing silver and silver halide from said emulsion layer, andthereafter further treating the resulting emulsion layer with an aqueoussolution containing an alkali metal ferricyanide and thereby oxidizingleuco dye in said emulsion layer to the full color intensity of the dye.

i2 :3. In the color processing of an exposed photograehic silver halideemulsion layer containing a color coupler that has been colordevelcpedto form a dye image, the.

improvement whichcomprises treating the said color developed emulsionlayer with an aqueous solutionvcon taining" ferric chloride,ethylenediamine' tetraacetic. acid," sodium thiosulfate and sodiumsulfite'and thereby solubilizing and removing silver and silver halidefrom said emulsion layer, and thereafter further treating the resultingemulsion layer with an aqueous solution containing potassiumferricyanide andthereby oxidizing leuco dye in saidemulsion layer tofull color intensity.

4. The process as described in claim 1 wherein the silver halideemulsion layer contains in excess of 20-0 mg. of silver per square foot.

References Cited by the Examiner V UNITED STATES PATENTS NORMAN G.TORCHIN, Primary Examiner.

LOUISE P. QUAST, Examiner.

1. IN THE COLOR PROCESSING OF AN EXPOSED PHOTOGRAPHIC SILVER HALIDEEMULSION LAYER CONTAINING A COLOR COUPLER THAT HAS BEEN COLOR DEVELOPEDTO FORM A DYE IMAGE, THE IMPROVEMENT WHICH COMPRISES TREATING THE SAIDCOLOR DEVELOPED EMULSION LAYER WITH AN AQUEOUS SOLUTION CONTAININGFERRIC CHLORIDE AND A THIOSULFATE SILVER HALIDE SOLVENT AND THEREBYSOLUBILIZING AND REMOVING SILVER AND SILVER HALIDE FROM SAID EMULSIONLAYER, AND THEREAFTER FURTHER TREATING THE RESULTING EMULSION LAYER WITHAN AQUEOUS SOLUTION CONTAINIG A FERRICYANIDE SILVER OXIDIZING AGENT ANDTHEREBY OXIDIZING LEUCO DYE IN SAID EMULSION LAYER TO FULL COLORINTENSITY.